1. Field of the Invention
The present invention relates to a driver assist information transmitter, a driver assist information receiver, and a driver assist information providing system.
2. Description of Relevant Art
A driver assist information to be typified by traffic information is provided to drivers driving his or her vehicle in diverse ways, such as television broadcast, radio broadcast, the indication on an electric bulletin board, and so on.
When the driver assist information is provided to a driver by means of radio broadcast, the following two communication techniques are generally used. One is the technique, in which the driver assist information is provided by means of AM radio broadcast or FM radio broadcast. The other is the technique, in which the driver assist information is provided as text information by means of FM multiple broadcasts.
As an example of such techniques, the technique disclosed in the Japanese unexamined patent application No. 2000-76587 is known.
In this application, a wireless communication technique is used in order to transmit the driver assist information to each driver (occupant) of a vehicle. In this application, still more concretely, the driver assist information is transmitted to a driver by means of the wireless communication between the mobile station and the wireless communication device to be provided on road.
When the driver assist information is transmitted using the radio broadcast technique, since bandwidth is narrow and the transmission rate is slow, this radio broadcast technique is unfit for the transmission of large amount of data. Thus, the amount of the information of the driver assist information to be supplied to a driver has a limitation.
When the driver assist information is transmitted using the wireless communication technique, on the other hand, the mobile station must pass through the area, wherein communication with the wireless communication device is possible, in order to obtain the driver assist information. Thus, if the contents of the driver assist information are the information, which changes frequently, such as traffic congestion information, a large number of the wireless communication devices are required so that the mobile station can obtain the driver assist information irrespective of the current position. In this case, since large economical burdens are required to provide a large number of the wireless communication devices, the realization has been difficult.
Therefore, the system, which can assist a driver of a mobile station, and which can provide up-to-date information to a driver of a mobile station irrespective of the current position of the mobile station and without limitation of the amount of data, has been required. That is, a driver assist information transmitter, a driver assist information receiver, and a driver assist information providing system, which can fulfill these requirements, have been desired.